<!DOCTYPE html>
<html lang="en">
<head>
    <meta charset="UTF-8">
    <meta name="viewport" content="width=device-width, initial-scale=1.0">
    <meta http-equiv="X-UA-Compatible" content="ie=edge">
    <title>Document</title>
    <style>
        div{
            width: 200px;
            height: 400px;
            border-top:5px solid red;
            border-left:1px solid orange;
            border-right: 3px solid rebeccapurple;
            border-bottom: 1px solid red;
        }

        input{
           border:none; 
           /* 四个边框都去掉 先写大的，后写小的 */
           border-bottom: 1px solid black;
        }
    </style>
</head>
<body>
    <div></div>
    请输入用户名<input type="text"><br/>
    请输入密码<input type="password">
</body>
</html>